pwt9: PWT 9.0 Dataset

#' PWT 9.0
#'
#' PWT version 9.0 is a database with information on
#' relative levels of income, output, inputs and productivity,
#' covering 182 countries between 1950 and 2014.
#' Released on: June 9, 2016
#'
#' Source: \url{http://www.rug.nl/research/ggdc/data/pwt/pwt-9.0}
#'
#' @format A data frame with 11830 rows and 47 variables:
#' \describe{
#'   \strong{Identifier variables}
#'   \item{countrycode}{3-letter ISO country code}
#'   \item{country}{Country name}
#'   \item{currency_unit}{Currency unit}
#'   \item{year}{Year}
#'   \item{}{}
#'   \strong{Real GDP, employment and population levels}
#'   \item{rgdpe}{Expenditure-siderealGDP atchained PPPs(in mil. 2005US$)}
#'   \item{rgdpo}{Output-siderealGDP atchained PPPs(in mil. 2005US$)}
#'   \item{pop}{Population (in millions)}
#'   \item{emp}{Number of persons engaged (in millions)}
#'   \item{avh}{Average annual hours worked by persons engaged}
#'   \item{hc}{Index of human capital per person, based on years of schooling (Barro/Lee, 2012) and returns to education (Psacharopoulos, 1994)}
#'   \item{}{}
#'   \strong{Current price GDP, capital and TFP}
#'   \item{ccon}{Real consumption of households and government, at current PPPs (in mil. 2005US$)}
#'   \item{cda}{Real domestic absorption, (real consumption plus investment), at current PPPs (in mil. 2005US$)}
#'   \item{cgdpe}{Expenditure-side real GDP at current PPPs (in mil. 2005US$)}
#'   \item{cgdpo}{Output-side real GDP at current PPPs (in mil. 2005US$)}
#'   \item{ck}{Capital stock at currentPPPs(in mil. 2005US$)}
#'   \item{ctfp}{TFP level at currentPPPs(USA=1)}
#'   \item{cwtfp}{Welfare-relevant TFP levels at current PPPs (USA=1)}
#'   \item{}{}
#'   \strong{National accounts-based variables}
#'   \item{rgdpna}{RealGDP at constant 2005 national prices (in mil. 2005US$)}
#'   \item{rconna}{Real consumption at constant 2005 national prices (in mil. 2005US$)}
#'   \item{rdana}{Real domestic absorption at constant 2005 national prices (in mil. 2005US$)}
#'   \item{rkna}{Capital stock at constant 2005 national prices (in mil. 2005US$)}
#'   \item{rtfpna}{TFP at constant national prices (2005=1)}
#'   \item{rwtfpna}{Welfare-relevant TFP at constant national prices (2005=1)}
#'   \item{labsh}{Share of labour compensation in GDP at current national prices}
#'   \item{delta}{Average depreciation rate of the capital stock}
#'   \item{}{}
#'   \strong{Exchange rates and GDP price levels}
#'   \item{xr}{Exchange rate, national currency/USD (market+estimated)}
#'   \item{pl_con}{Price level of CCON (PPP/XR), price level of USA GDPo in 2005=1}
#'   \item{pl_da}{Price level of CDA (PPP/XR), price level of USA GDPo in 2005=1}
#'   \item{pl_gdpo}{Price level of CGDPo (PPP/XR),  price level of USA GDPo in 2005=1}
#'   \item{}{}
#'   \strong{Data information variables}
#'   \item{i_cig}{0/1/2: relative price data for consumption, investment and government is extrapolated (0), benchmark (1) or interpolated (2)}
#'   \item{i_xm}{0/1/2: relative price data for exports and imports is extrapolated (0), benchmark (1) or interpolated (2)}
#'   \item{i_xr}{0/1: the exchange rate is market-based (0) or estimated (1)}
#'   \item{i_outlier}{0/1: the observation on pl_gdpe or pl_gdpo is not an outlier (0) or an outlier (1)}
#'   \item{cor_exp}{Correlation between expenditure shares of the country and the US (benchmark observations only)}
#'   \item{statcap}{Statistical capacity indicator (source: World Bank, developing countries only)}
#'   \item{}{}
#'   \strong{Shares in CGDPo}
#'   \item{csh_c}{Share of household consumption at current PPPs}
#'   \item{csh_i}{Share of gross capital formation at current PPPs}
#'   \item{csh_g}{Share of government consumption at current PPPs}
#'   \item{csh_x}{Share of merchandise exports at current PPPs}
#'   \item{csh_m}{Share of merchandise imports at current PPPs}
#'   \item{csh_r}{Share of residual trade and GDP statistical discrepancy at current PPPs}
#'   \item{}{}
#'   \strong{Price levels, expenditure categories and capital}
#'   \item{pl_c}{Price level of household consumption,  price level of USA GDPo in 2005=1}
#'   \item{pl_i}{Price level of capital formation,  price level of USA GDPo in 2005=1}
#'   \item{pl_g}{Price level of government consumption,  price level of USA GDPo in 2005=1}
#'   \item{pl_x}{Price level of exports, price level of USA GDPo in 2005=1}
#'   \item{pl_m}{Price level of imports, price level of USA GDPo in 2005=1}
#'   \item{pl_k}{Price level of the capital stock, price level of USA in 2005=1}

#'   ...
#' }
#' @source Feenstra, Robert C., Robert Inklaar and Marcel P. Timmer (2015),
#' "The Next Generation of the Penn World Table"
#' American Economic Review, 105(10), 3150-3182,
#' available for download at\url{www.ggdc.net/pwt}
"pwt9"